54 
also resemble emarginata and some individuals might, alone, be referred 
to that species. It lacks the peculiar texture of that species as well as the 
wide spire at the shoulder, and the aperture and columellar region are, for 
the most part, different. As far as shell form is concerned, the two species 
in the north approach each other very closely in many respects. The new 
variety is very abundant in the localities cited and the material includes 
all ages, the smallest being 2-5 mm. in length and having barely two 
whorls. The large aperture appears to develop at an early period in the 
life of the snail. The variety is named in honour of Mr. Jack T. Kemp, a 
companion of the junior author on his Canadian trips. 
This is probably the form recorded as catascopium by Whiteaves from 
Mistassin, Ozhiski, and Sutton lakes, Attawapiskat, Kawinogans, and 
Winisk rivers. It may also include some material from Manitoba listed as 
emarginata. Dali records emarginata from English river, and this may also 
be founded in the new form of catascopium. No material like the typical 
emarginata from Maine lias been seen from northern Ontario. Mozley 
records emarginata from Manitoba and as typical emarginata occurs in 
northern Wisconsin it probably has a wide northward range. There are 
several ecological races of this species that should be found in the lakes of 
northern Ontario and Manitoba. 
Fossaria obrussa decampi (Strong) 
Bamaji, Hamilton, Cat, Pashkokogan lakes, and outlet of Kapikik 
lake. All of the specimens are small and immature, but without doubt 
referable to this race of obrussa. Recorded from Manitoba but not from 
northern Ontario, so far as known. It is highly probable that the material 
recorded by Whiteaves as Limnaea galbana (Say) (not Haldeman) from 
Kawinogans, Attawapiskat, Kanuchuan, and Winisk rivers and Ozhiski 
and Wapikopa lakes is all referable to decampi, which is the common small 
lymnaeid of the north, both recent and in post-Cdacial deposits. The 
form called galbana (Say) is rare, occurring so far as known as a fossil only 
in the eastern part of the United States. The living representative of the 
genus, variety sayi, is somewhat different from the fossil form and occurs 
only, so far as recorded, in the area of the Great Lakes. 
Fossaria exigua (Lea) 
Bamaji Lake outlet. Rather longer-spired than the typical form of 
the species, but referable to it without doubt. Not before recorded from 
central Ontario. Listed from Manitoba by Mozley. 
Bulimnea megasoma (Say) 
Marchington river, very abundant; Bamaji lake, not common; Cat 
and Hill lakes, rare. Recorded from lake St. Joseph by Whiteaves and 
from Manitoba by Mozley. This monotypic group is distributed from 
northern Ohio (Stark county) to Echinamish lake in latitude 57 degrees, 
and is apparently most abundant in the northern part of the United States 
and southern Canada. It is the most abundant shell obtained by the Cahn 
party. The individuals are large and fine in colour, the size of a majority of 
the specimens being between 45 and 50 mm. in length. The young and 
immature shells are very thin. 
